Rocks

@http://science.nationalgeographic.com/science/earth/inside-the-earth/rocks-article/

@http://geology.com/rocks/

@http://sciencenetlinks.com/esheets/rocks/

@http://www.fi.edu/fellows/fellow1/oct98/create/

@http://www.mylearning.org/rocks-at-cliffe-castle-museum/p-1148/

@http://www.learner.org/interactives/rockcycle/diagram.html